How to calculate Laws of Thermal Radiation

In summary, Star X has a surface temperature of 10,000 K and emits radiation according to the Stefan-Boltzmann Law. Assuming it is a black body, its emissivity is unity and the power emitted per square meter can be calculated by multiplying the absolute temperature to the 4th power by the Stephan-Boltzmann constant. Additionally, the dominant electromagnetic radiation emitted by Star X can be determined using Wien's Law by entering the temperature in nanometers. These formulas may be difficult to understand and use, especially for online learners.
  • #1
JayWilks
2
0
1. Star X has a surface temperature of 10,000 K. How much power does it emit per square meter? Enter numbers only. Do not enter units (watt/m2 is assumed)
2. Star X has a surface temperature of 10,000 K. What is the wavelength of the dominate electromagnetic radiation that Star X emits? Enter numbers only. Do not enter units (nanometers, nm is assumed)
I know that I'm supposed to use Stefan-Boltzmann Law for the first question and Wien's Law for the second but I have no idea on how to go about it. Any help would be truly appreciated
 
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  • #2
Radiation emitted is computed for things here on Earth by multiplying the absolute temperature to the 4th power by the Stephan-Boltzmann constant and the emissivity. If you assume the star is a black body, the emissivity is unity.
 
  • #3
LawrenceC said:
Radiation emitted is computed for things here on Earth by multiplying the absolute temperature to the 4th power by the Stephan-Boltzmann constant and the emissivity. If you assume the star is a black body, the emissivity is unity.

I was doing okay in this course until this lesson. I am taking this class online and this all seems way over my head, even what you just stated to me I'm having a hard time understanding. I think I found the formulas to get my answers but I don't know how or if they can be inputted to a calculator.
 

FAQ: How to calculate Laws of Thermal Radiation

1. What is thermal radiation?

Thermal radiation is a type of electromagnetic radiation that is produced by the movement of particles in a substance at a certain temperature. It can be felt as heat and can be emitted and absorbed by any matter with a temperature above absolute zero.

2. What are the three laws of thermal radiation?

The three laws of thermal radiation are Stefan-Boltzmann law, Wien's displacement law, and Kirchhoff's law. Stefan-Boltzmann law states that the total energy emitted by a blackbody is proportional to the fourth power of its absolute temperature. Wien's displacement law states that the wavelength of maximum emission of a blackbody is inversely proportional to its absolute temperature. Kirchhoff's law states that the ratio of emissive power to absorptive power of a body is equal to the emissivity of the body.

3. How do you calculate the radiation emitted by a blackbody?

The radiation emitted by a blackbody can be calculated using the Stefan-Boltzmann law, which states that the total energy emitted per unit time by a blackbody is equal to σT4, where σ is the Stefan-Boltzmann constant (5.67 x 10^-8 W/m^2K^4) and T is the absolute temperature in Kelvin.

4. What is the significance of the emissivity of a body?

The emissivity of a body is a measure of the efficiency with which it emits thermal radiation compared to a perfect blackbody at the same temperature. It is a dimensionless quantity between 0 and 1, where 0 represents a perfect reflector (no radiation emission) and 1 represents a perfect blackbody (maximum radiation emission).

5. How does thermal radiation transfer heat?

Thermal radiation transfers heat through the exchange of electromagnetic waves between objects with different temperatures. The hotter object emits more radiation than the cooler object, resulting in a net transfer of thermal energy from the hotter object to the cooler object. This process is known as thermal radiation heat transfer and is an important mechanism for heat transfer in various systems.

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